The Environment Agency has called on River Thames users to keep working together to control floating pennywort. More than 63 tonnes of the invasive water plant has been removed from the Thames over the winter and spring but there is still more to do.

Because of the efforts of the Environment Agency and some local groups, where there were large rafts of the plant in some areas, there are now only a few small traces of regrowth. The Environment Agency continues to monitor and remove new growth of this very invasive and destructive plant. However, the summer is the peak season for floating pennywort growth which can have detrimental impacts on watercourses. Large blooms of the plant affect the oxygen content of rivers, reduce biodiversity, can damage important habitats and potentially increase flood risk.

As part of the annual maintenance programme, the Environment Agency has been managing floating pennywort for several years in locations such as the River Wey and the Foudry Brook. But more help and support is needed from the public and river users if we are to succeed in controlling the spread of this destructive plant.

Daryl Buck, from the Environment Agency, said:

We actively monitor more than 200km of the River Thames. Our aim is to eradicate floating pennywort from the main River Thames completely, but we can only achieve this with the continued cooperation of key members of the community.

Early intervention is the most efficient way to keep on top of this damaging plant as it can grow up to 20cm per day! We are urging riverside owners to keep an eye on their watercourse and report any new growth to us. We also would like to hear from river users such as anglers, boaters and canoeists who may come across the plant when out and about enjoying the river.

One success story so far has been the work undertaken earlier this year in the Abbey River near Chertsey. Floating pennywort established itself last season in the popular watercourse, causing all kinds of issues for river users like anglers and kayakers as well as landowners.

Ian Penny, secretary of a local angling club, said:

This non-native plant is very aggressive and plays havoc for fish and plant life. The Environment Agency did an absolutely fantastic job of totally removing the floating pennywort from over a mile stretch of the river. Everyone who enjoys the river has a responsibility to help the situation by reporting any new sightings via the Plant Tracker website.

Richard Atkinson, Policy Officer for British Canoeing, said:

British Canoeing takes its environmental responsibility very seriously and wants all water users to have fun and enjoy the natural environment. Non-native invasive species like pennywort have a significant impact on biodiversity, the environment and paddling.

We will be encouraging our members to report any sightings via the app and by reinforcing the importance of the check, clean, dry procedure after paddling.

People can visit the Plant Tracker website or download the Plant Tracker app co-developed by the Environment Agency to enable river users to record sightings of floating pennywort to help concentrate removal efforts where they are most needed.

Floating pennywort was introduced into the UK as an ornamental plant. For more information pond owners are encouraged to go to the plantwise campaign.

Ends

Notes to Editors

Photographs are available on request.

Floating pennywort is an aggressive invasive non-native species of plant, introduced to this country as an ornamental aquatic plant. It tends to favour slower moving watercourses. It is now widespread in southern and eastern England, including parts of the River Thames and its backwaters between Reading and Kingston and the River Wey.

The Environment Agency is under no obligation to remove floating pennywort, however we do have discretion to remove it under our statutory powers. Riparian owners are also not obliged to remove it, unless it can be shown that they planted it, though if it is on their land they do have a duty to take reasonable action to ensure it does not cause damage to neighbouring properties.

Boaters should not pass though through clumps of the plant. It can break off and spread downstream or carry it upstream. Visually check your craft regularly and, if safe to do so, remove any visible weed, placing it well away from any river or other water body.

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